Method of forming an electric light bulb socket



Oct. 8, 1968 D. MORANDU ZZO METHOD OF FORMING AN ELECTRIC LIGHT BULBSOCKET 2. Sheets-Sheet 1 Filed March 8, 1966 INVENTOR. DAR/O MORANDUZZOA TT'OR/VEYS.

. 8, 1968 I o. MORANDUZZO 3,404,453

'METHOD OF FORMING AN ELECTRIC LIGHT BULB SOCKET Filed March a, 1966 2Sheets-Sheet 2 I N VEN TOR. DAR/0 MURANDUZZO A TTOAA/EYS'.

United States Patent 3,404,453 METHOD OF FORMING AN ELECTRIC LIGHT BULBSOCKET Dario Moranduzzo, Via Aretina 161, Florence, Italy Filed Mar. 8,1966, Ser. No. 532,771 Claims priority, application Italy, June 18,1965, 14,251/65, 14,252/65 3 Claims. (Cl. 29-628) ABSTRACT OF THEDISCLOSURE An electric light bulb socket construction comprises firstand second connecting cables which are connected together in the form ofa series circuit. A length of one of the cables is cut away and the twoends are connected to respective ones of two spaced apart flat terminalmembers which extend outwardly at substantially right angles from thesevered cable in a direction away from the other cable. A feature of theconstruction is that a lamp receiving socket is formed by either moldingor stamping a plastic socket around the two cables at the location ofthe flat terminals in a manner to embed a portion of the terminalswithin the socket thus formed with the terminals arranged in spacedopposed relationship. The socket thus formed is designed to receive alamp having a base with a terminal element on each side of the basewhich will engage a respective terminal element of the socket.

This invention relates in general to electrical connecting devices forlight bulbs and in particular to a new and useful electrical connectingline having socket means thereon for connecting a plurality of smalllight bulbs and to a method for making such line.

The present invention particularly relates to a type of electrical linewhich may be used, for example, for Christmas tree light bulbconnections. The present invention is an improvement over the prior art,particularly in respect to the inexpensive construction of an electricalline for this purpose and also to the method for manufacturing the same.The invention construction includes socket means formed at selectedintervals along the length of parallelly running connecting cables. Thesocket means are formed at spaced intervals along the cables by pressureforming a plastic socket directly over the cable. The invention makes itpossible to form any number of relatively small sized socket bases of athermoplastic material for the purpose of supporting preferably plug-intype lamps or bulbs. The arrangement is particularly applicable for usein a series line connection which includes an outgoing cable connectedat its outer end to a return cable and with miniature socket elementsbeing formed across the two cables at spaced locations along theirlength. With the invention, one of the cables which is to supply thecurrent to the bulbs in a socket is bared and severed and the twosevered ends are connected to respective conductive terminal elements.The terminal elements advantageously comprise sleeve members which arefitted over the conductive ends of the bared cables and include portionsbent at right angles thereto which will form terminals for connecting alamp into the severed line. The two terminals are oriented in a fixedspaced relationship so that they face each other and then a socketmember of plastic is formed directly over the two cables and theterminals which become embedded in opposite walls of a lamp receivingsocket extension. The socket extension is advantageously made with anoncircular recess to permit the plug-in connection of a lamp bulb of atype having exposed contacts which will be aligned with the contactterminals formed in the plastic material.

In the preferred method of the invention it is a simple matter to firstform the two current lines with a terminal plug for insertion into ahouse current receptacle. The lines are joined together at theiropposite ends to join them in a series circuit. Thereafter, theinsulation is removed from one of the connecting cables at selecteddistances along its length. A stamped conductive terminal of U-shapedconfiguration is then positioned so that laterally projecting lugs oneach side may be electrically and mechanically connected to the baredcable. The web center of the U-shaped portion is then severed, leavingtwo spaced metal terminals oriented in spaced relationship to each otherwhich form terminals after the bared length of cable therebetween isalso severed. Thereafter, a plastic socket member is formed directlyover the spaced terminals to complete the electrical line formation forone socket. The socket projects from the line and the terminals becomepartially embedded in opposite walls so that they project for electricalconnection.

Accordingly it is an object of the invention to provide an improvedelectrical connecting circuit, particularly for small sized lamps.

A further object of the invention is to provide an electrical connectingcircuit which includes a series connecting cable extending outwardlyfrom a terminal plug and then backwardly to the plug, with one of theconnecting branches being severed at least at one location along thelength thereof and with metallic terminals aflixed thereto at thesevered ends which are arranged at spaced locations and including astamped or molded plastic socket formation formed around the terminalsin a manner such that the socket which is formed holds the terminals inspaced relationship for completing an electrical connection with a bulbinserted into the socket.

A further object of the invention is to provide an improved method offorming an electrical light connection, particularly for lamps, in whicha molded socket is formed around spaced terminals which are electricallyconnected to the cables of the circuit in a manner such that the spacedterminals are embedded in the avall at spaced locations for receiving alamp therein and making electrical contact therewith.

A further object of the invention is to provide an electrical currentline for relatively small sized lamps which is simple in design, ruggedin construction and economical to manfacture.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,its operating advantages and specific objects attained by its use,reference should be had to the accompanying drawings and de scriptivematter in which there is illustrated and described a preferredembodiment of the invention.

In the drawings:

FIG. 1 is an elevational view of a Christmas tree bulb connectingcircuit constructed in accordance with the invention;

FIG. 2 is a partial transverse sectional view with one of the socketsindicated in FIG. 1, with the lamp bulb shown removed from the socket;

FIG. 3 is a top plan view of one of the sockets indicated in FIG. 1, butwith the light bulb removed;

FIGS. 4 to 7 are partial plan views of a portion of the connecting linesshowing the steps of forming the socket thereon in accordance with themethod of the invention; and

FIG. 8 is a perspective view of a terminal plug employed in accordancewith the method of the invention for forming the socket terminals.

Referring to the drawings in particular, the invention embodied thereincomprises a flexible bifilar strip generally designated 1 which includestwo conductor cable branches 2 and 3 which are connected at their endsto respective terminals of a plug member 6 and are joined to gether attheir opposite end and covered by means of a shield member which issecured to the strip 1.

'In accordance with the invention, the electrical circuit connectionincludes a plurality of socket members 4 which are formed in accordancewith the method of the invention by stamping or molding the sockets of athermoplastic material over the strip 1 at selected locations along itslength. The thermoplastic material is also electrically insulating.

As indicated in FIG. 2, the socket 4 is formed after the insulation isremoved from a short length of one of the connecting cable branches, inthis instance the branch 2. The cable 2 is severed to form baredterminals 9, 9 which are then each connected to a separate lamp socketterminal member 8. For this purpose each socket terminal member 8includes a cylindrical portion 8a which fits over the associatedterminal 9 and is secured thereto such as-by press-fitting or crimping.The portion 8a stands at substantially right angles to the main terminalportions so that they may be connected to the cables in a simple manner.The outer ends of the terminals 8, 8 are then arranged in spacedparallel relationship and a socket member 4 is formed by stamping ormolding a plastic material around the cables 3 and 2 and projectingoutwandly therefrom in the from of a socket extension 4a which is atright angles to a socket base 4b. The socket extension 4:: is providedwith a recess or cavity 10 for receiving a base or foot portion 11 of alamp bulb 12. The lamp bulb 12 is of a type which includes exposedterminals 13, 13 and is of a shape such that it may be press-fittedwithin the socket 10. The terminals 8, 8 are embedded in opposite sidesof the socket 12, and when the lamp 12 is properly oriented with itsbase v11 in the socket, the terminals 13, 13 are connected to respectiveterminals 8, 8.

' The first socket assembly 4 is advantageously formed along a length ofthe strip 1 at a fixed distance from the plug 6 which is established inaccordance with the particular light set which is to be employed. Thesockets 4 are formed in a rigid manner at the fixed location indicatedalong the strip 1, and the construction is such that the contactterminals will be anchored within the plastic, there being little or nopossibility that they may become loosened. By stamping or molding orotherwise pressureforming the plastic material socket it is assured thata permanent insulation will be applied around the severed portions ofthe connecting cable and that the contacts will be protected againstpenetration by moisture and may be used outdoors. By forming the socketelements in situ, the manufacturing process is vastly simplified andthus is less expensive.

In the preferred method of the invention, a U-shaped terminal membergenerally designated 8', as indicated in FIG. 8, is advantageously usedfor forming the two terminals 8, 8. This member includes laterallyprojecting trough-shaped elements 8a, 8a on each side of the top, and acentral web portion or bight portion 8b for-med between the lower endsof the terminals 8, 8. The troughshapedmembers 8a form channels forpermitting easy orientation of the terminal elements to the wires in themethod of the invention.

As indicated in FIGS. 4 to 7, the process of the invention is carriedout by first locking a length of the cable strip 1 into a locking jighaving clamping means schematically indicated 18. Thereafter a length lof the cable 2 is bared by removing the insulation covering and also aportion of the strip webbing of the strip 1 is removed. The terminalmember 8 is then inserted so that the troughshaped portions 8a, 8a arealigned over the cable length l and the sides of the trough-shapedportions are bent over the cable to provide a secure electricalconnection which may also be soldered.

In FIG. 6 it is indicated how the web portion 8b is removed and theouter ends of the terminals 8, 8 are bent outwardly, as indicated at 19.As indicated in FIG. 7, the cable lying between the terminal portions 8,8 is then severed. Thereafter, the plastic socket 4 is then formeddirectly over the bifilar strip 1 in a manner such that the socketportion 4a projects outwardly from the cylindrical base portion 4b. Bystamping the socket member 4 in situ, it is assured that the insulationaround the exposed length of wire I 'will be absolutely maintained andprotected from any weather effects.

While a specific embodiment of the invention has been shown anddescribed in detail to illustrate the application of the inventiveprinciples, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:

1. A method of forming an electrical line connection for small lightbulbs using an electrical line having two conductor cables arranged inspaced parallel relationship and connected together in a series circuitfashion, each of these cables being covered with insulation, comprisingremoving the insulation to bare a length of one of said two conductorcables, afilxing the inner ends of two spaced terminal members to thebared cable and electrically connecting each of the inner ends to thehatred cable at respective spaced locations and in a manner so that theterminals extend outwardly at spaced locations and at substantiallyright angles to the bared cable, severing the bared length of cableintermediate the length thereof to form two electrically isolated spacedends, forming a plastic socket with a lamp receiving recess around atleast the bared cable in the area of the connection to the respectiveterminal inner ends and embedding at least a portion of the spaced apartterminals in the plastic socket so that they are oriented in spacedopposed relationship with at least a portion of the terminals exposed inthe lamp receiving recess, said lamp receiving recess being formed ofthe plastic in a configuration to receive a socket of a lamp bulb forconnection of the bulb to the terminals in the socket.

2. A method according to claim 1, using a substantially U-shapedterminal member including a central bight portion and two leg portionsfor forming the connecting terminals and comprising positioning theterminal memher with the ends of the leg portions engaged with therespective cable spaced ends, and mechanically clamping the terminalmember leg portion ends to the respective cable ends, and thereaftersevering the bight portion of the U-shaped terminal to form two separateterminals which project outwardly from the cable.

3. A method according to claim 2, wherein the ends of the leg portionsof said terminal member which are formed by cutting away said bightportion are bent outwardly prior to the forming of said plastic socketto permit these ends to be embedded in the plastic socket.

References Cited UNITED STATES PATENTS 1,722,737 7/1929 Eckstein et al.339-- 1,728,938 9/1929 Kirschstein 3l5-l92 1,979,485 11/1934 McPartlinet al. 33959 2,071,948 2/1937 Peters 339157 2,723,383 11/1955 Franc339-176 2,944,330 7/1960 Swick 339217 XR MARVIN A. CHAMPION, PrimaryExaminer.

P. A. CLIFFORD, Assistant Examiner.

